LESSON IV 



Staining of Hanging Drop Cultures Gram's Method of Staining 

 Staining of Pus Curdling Ferment. 



Staining of Hanging Drop Cultures 

 Bacillus filamentosus. 



(a) Carefully remove the cover-glass and allow the drop 

 culture to dry in the air. 



(b) Wipe off as much of the vaseline as possible. 



(c) Pass the film three times through the flame. 



(d) Carefully stain in Loffler's methylene-blue for two 

 to three minutes. 



(e) Wash very gently in water. 



(/) Dry the film between folds of filter-paper, and when 

 it is quite dry mount in xylol balsam. 



Examine it with a high power, and then with -^ in- 

 oil immersion. Observe the beautiful network of 

 filaments. 



Gram's Method of Staining 



Streptococcus pyogenes. 



Stain the hanging drop cultures of Streptococcus 

 pyogenes by this method. 



